The invention relates to blood infusion apparatus for rapid infusion of life saving fluids into a patient, and more particularly to improved blood infusion boxes containing a bladder against which unit bags of life sustaining fluids are pressed by means of a front door and are inflated to facilitate more rapid infusion of the fluid than occurs action of gravity.
The most common technique for rapid infusion of blood and other life sustaining fluids in the United States, and for that matter, in the world, is use of sleeve type infusion bags of the type manufactured by Baxter Travenol. Roughly 65 million of the sleeve-type infusion bags have been sold around the world in the last dozen or so years. They are ordinarily suspended by a hook on an infusion stand. Unit bags containing the fluid to be infused are inserted into the deflated sleeve, which then is inflated by means of a small hand bulb which is repeatedly squeezed by an attendant or whoever happens to be available to squeeze it. This device has several disadvantages. The inflatable sleeve or "cuff" expands in all directions so that a large volume of air is necessary for effective pressurization. The sleeve type infusion bladder is usually suspended by a single loop or hook from the infusion stand, leading to rotation and instability of the infusion system. Furthermore, it is necessary to completely deflate the sleeve type infusion bladder in order to allow access to or removal of the unit bag containing the life sustaning fluid to be infused. Furthermore, it is usually difficult to see when the blood or fluid in the unit bag is nearing exhaustion. Usually, if red blood cells must be infused, they are initially in the form of a sticky solution, since blood received from donors is ordinarily centrifuged to separate the different useful components thereof. When red blood cells are required, the sticky red fluid must be mixed with saline solution and brought up to body temperature before it reaches the infusion needle. Often, a unit bag of blood cells are infused with a unit bag of saline solution. Typically, the unit bag of saline solution is manually squeezed into and mixed with the red blood cells in, for example, a one liter unit bag. This is a bothersome, time-consuming procedure.
Typically, due to the coldness and high viscosity of the blood cells (which have been kept cold in a refrigerator), a rather high level of pressure is required in the sleeve-type infusion bladder. Another problem with use of the sleeve type infusion bladders is that the above-mentioned hand bulb type pumps usually require a person, such as a nurse, or sometimes even a physician, to spend his or her very valuable time simply operating the hand pump.
It should be appreciated that medical personnel who have to rapidly infuse life sustaining fluids frequently must use infusion equipment under extreme emergency conditions. Sometimes, two or three liters or, in some cases, even up to eight or ten liters of life sustaining fluid have to be transferred very quickly into the patient. The amount of time required to set up the infusion apparatus may be critical. In some instances, many liters of blood have to be infused into a patient within a half hour of time in order to save the patient's life. The environment in which emergency rapid blood infusion must be accomplished can include hospital emergency rooms, wherein nurses, paramedics, etc., are available to set up and operate the infusion devices. In other cases, personnel and emergency vehicles have been sent to the scene of an accident, whereat the infusion devices must be rapidly set up and operated by available personnel. In many instances, the efforts of an extremely valuable person, such as a paramedic or even a surgeon may be required to keep pumping the hand pump in order to keep the sleeve type infusion bladder adequately pressurized. This is obviously a serious problem if that person has to interrupt other medical tasks which must be performed often under the pressure of inadequate available time.
Under the pressure of situations under which blood must be rapidly infused under emergency circumstances, occasionally the squeeze bulb type pumps are not continuously operated, and sometimes they are forgotten. This can result in severe consequences to the patient if he does not receive an adequate amount of the fluid being infused in an adequate amount of time, or if the fluid being infused becomes warm and then contaminated due to bacterial action.
As a result of the difficulties that have been experienced with the above-mentioned sleeve-type infusion bladders, personnel that have to administer blood or other life-sustaining fluids to patients under emergency circumstances frequently have a very "negative" attitude about blood infusion tasks because of bad experiences that they have had resulting from the inadequacies of the blood infusion equipment used, especially the large amount of time that has been required to set up sleeve type blood infusion apparatus.
In England, a device known as the "Norfolk and Norwich Infusion Box" and described in Anesthesia, Volume 35, pages 1211-1214, has grealy improved the speed and reliability of infusion procedures. The device, referred to herein as an "infusion box", consists of a rigid back wall, two rigid side walls, and a hinged door at the front with a rigid transparent window therein. When in use, the door is held shut with a quick-release latch. Expansion knobs at the top of the back wall and at the top of the back surface of the door support an infusion bladder known as a Fenwall Infuser. A blood or fluid container is suspended from the knob on the back of the door. The door is closed and secured by the quick release latch, and the infusion bladder is inflated in the usual manner by means of the squeeze bulb hand pump. A major advantage of this system is that a much smaller volume of air is necessary to adequately pressurize the infusion bag. Furthermore, since the blood containing "unit bag" is not placed within the infusion sleeve, its contents are easily visible through the transparent door. Although this device is being used to some extent in Great Britain, attempts to introduce it to the market in the United States have completely failed, due to various shortcomings of the Norfolk and Norwich infusion boxes which have been introduced to date. Several different sizes of "unit bags" are commonly used for life-sustaining fluids, including half liter and liter bags; it is essential that an infusion box be able to accommodate either. The prior models of the Norfolk and Norwich Infusion Box include an awkward, adjustable, unit bag supporting device that extends well above the upper end of the infusion box. It should be appreciated that in a typical emergency environment in which blood infusion apparatus is used, whatever infusion apparatus is used must have a great deal of physical strength and durability, or else it soon will be bent, broken otherwise damaged. Medical liability laws in the United States are much more severe than those in Great Britain, and introduction of any equipment that has even minor shortcomings that may result in injury to either the patients on which the equipment is being used or the personnel operating them can subject physicians, hospitals, ambulance companies, or the state to enormous legal liability. Equipment with even minor apparent shortcomings that might cause such injury and result in such liability will not be accepted by the U.S. market.
The available models of the Norfolk and Norwich Infusion Box, although they do avoid the long "set up" time of the sleeve type infusion bladders, nevertheless do not avoid the problems of requiring a person almost to continuously operate the squeeze bulb pump. Furthermore, these models are easily damaged in the environments in which they are stored and operated. The reaction of U.S. medical supply companies, hospital personnel, physicians, has generally been that they are not interested in adopting the Norfolk and Norwich device, and instead prefer to continue using the sleeve type infusion bags, which, although they typically have a life of only approximately one month due to the rough treatment which they usually receive, are relatively inexpensive. Furthermore, this use is so common in the medical community that, despite their shortcomings, their use does not constitute a basis for a malpractice claim.
In view of the foregoing considerations, it is clear that there has long been a great need for a greatly improved, inexpensive, highly reliable, highly durable blood infusion apparatus and method which has a short set up time, does not require large amount of time by one or more persons to keep the bladders inflated to the correct pressure, and allows rapid replacement of empty unit bags of blood or other life sustaining fluid.
It is another object of the invention to provide a greatly improved infusion box that avoids the shortcomings of the Norfolk and Norwich Infusion box and which is accepted by the United States medical emergency equipment industry.
It is another object of the invention to provide a blood infusion apparatus which avoids the need for medical equipment personnel be continuously concerned about the inflation level of the bladders which pressurize the life sustaining fluid containing bags.